The first thing to accept is that a royalty statement is an accounting document, not a report card. It is organised around territories, platforms and reporting periods rather than around songs, which is why the totals rarely match the numbers you see on any artist dashboard.
Focus on four things: the reporting period, the territory, the number of units, and the rate applied. Everything else is usually a subdivision of those. A song that appears fifteen times on one statement is typically the same song counted across different countries and subscription tiers.
The gap between dashboard plays and paid streams is normal and has several causes, including trial accounts, offline listening reconciled later, and the lag between activity and reporting. If the discrepancy is large and persistent, that is worth a query to your distributor. If it is small and consistent, it is simply how the system reports.